1. Field of the Invention
This invention relates to a timing assembly for an internal combustion engine. More specifically, this invention relates to a camshaft sprocket for use with a position sensor to indicate the angular position of a camshaft.
2. Description of the Prior Art
A typical internal combustion engine has an engine block with a plurality of cylinders each having a reciprocally movable piston disposed therein which defines a combustion chamber. The engine block supports a crankshaft interconnected by connecting rods to the pistons so that as the pistons move linearly within the cylinders they produce rotation of the crankshaft. The engine also includes at least one camshaft which is supported so as to actuate valves that control flow of air, fuel and exhaust to and from the combustion chambers. Sprockets are attached to the ends of the crankshaft and the camshaft(s) and a timing belt or chain interconnects the crankshaft to the camshaft(s). The diameter of the crankshaft sprocket is half the diameter of the camshaft sprocket so that for every two full rotations of the crankshaft the camshaft rotates once. The timing belt or chain ensures that the camshaft rotates properly to actuate the valves at the appropriate time in relation to the position of the pistons.
Modern engines utilize computer control and various sensors to control engine functions such as ignition timing and fuel injection operation. These sensors relay information to the computer for processing and then transmitting commands to the devices to control various aspects of engine operation, such as fuel injection and ignition park timing. Typically, the computer coordinates these devices by referencing the position of a particular piston, or triggering piston, specifically when it attains a top dead center position within its cylinder (TDC). The timing of the engine in relation to the piston's position is critical in maintaining efficient engine operation and controlling engine emissions.
Many types of sensors for computer control have been employed to track the angular position of an engine crankshaft and camshaft(s) for timing purposes. Specifically, sensors have been employed to detect the position of the camshaft sprocket attached to one end of the camshaft, which position correlates to the position of the piston because of its connection to the crankshaft by the timing belt or chain. However, this configuration has proven to be problematic from a packaging standpoint due to the very limited space constraints of a modern engine and its associated vehicle.